The milestone is the maiden test flight of its Orion spacecraft, a launch that has come into sharper relief in the three months since NASA and manufacturer Lockheed Martin announced it.

As planned, an unmanned Orion capsule will begin its journey at Cape Canaveral and take two loops around Earth before splashing down in the Pacific Ocean. What's now clear is that the capsule will be sent far beyond the lower Earth orbit of the International Space Station.

In Florida, the test flight, which will cost $375 million, will provide Kennedy Space Center with some badly needed work. The retirement of the shuttle led to the loss of at least 6,000 jobs. Lockheed Martin plans to employ as many as 400 workers for Orion at Cape Canaveral as it approaches the test flight.

At its peak, Orion's orbit is expected to extend nearly 3,700 miles from Earth — the farthest a NASA spacecraft built for humans has gone since the early 1970s.

That distance is "significantly higher than human spaceflight has gone since Apollo," said Larry Price, Orion deputy program manager at Lockheed Martin. "The reason for that is so we can get a high-energy entry so we can stress the heat shield."

The test will determine whether Orion can survive the re-entry into Earth's atmosphere — where temperatures are expected to reach 4,000 degrees — in preparation for a human flight in 2021. NASA hopes that Orion eventually can carry astronauts back to the moon or to nearby asteroids.